U.S. patent number 9,432,875 [Application Number 14/556,324] was granted by the patent office on 2016-08-30 for call admission control.
This patent grant is currently assigned to KT CORPORATION. The grantee listed for this patent is KT CORPORATION. Invention is credited to Jae-Ho Chung, Kyu-Jeong Han, Yung-Ha Ji, Wi-Sang Rho.
United States Patent |
9,432,875 |
Chung , et al. |
August 30, 2016 |
Call admission control
Abstract
The disclosure is related to a method of adaptive call admission
control in a base station. When a call access request is received
from a user equipment determination may be made as to whether an
available call admission capacity of the base station reaches a
first limit. When the available call admission capacity of the base
station reaches the first limit determination may be made as to
whether the received call access request is for a preferred call.
Then, determination may be made as to whether a reserved call
admission capacity reaches a second limit when the received call
access request is for the preferred call. When the reserved call
admission capacity has not reached a second limit, access of the
user equipment associated with the received call access request may
be allowed.
Inventors: |
Chung; Jae-Ho (Seoul,
KR), Rho; Wi-Sang (Seoul, KR), Ji;
Yung-Ha (Gyeonggi-do, KR), Han; Kyu-Jeong
(Gyeonggi-do, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
KT CORPORATION |
Gyeonggi-do |
N/A |
KR |
|
|
Assignee: |
KT CORPORATION (Gyeonggi-do,
KR)
|
Family
ID: |
49548982 |
Appl.
No.: |
14/556,324 |
Filed: |
December 1, 2014 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20150087326 A1 |
Mar 26, 2015 |
|
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
13889636 |
May 8, 2013 |
8929910 |
|
|
|
Foreign Application Priority Data
|
|
|
|
|
May 14, 2012 [KR] |
|
|
10-2012-0050853 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H04W
48/06 (20130101); H04W 28/08 (20130101); H04W
28/0289 (20130101); H04L 47/10 (20130101) |
Current International
Class: |
H04W
72/00 (20090101); H04W 48/06 (20090101); H04W
28/08 (20090101); H04W 28/02 (20090101); H04L
12/801 (20130101) |
Field of
Search: |
;455/453,452.1,418
;370/237 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
10-2005-0114589 |
|
Dec 2005 |
|
KR |
|
10-2007-0027468 |
|
Mar 2007 |
|
KR |
|
10-2008-0054654 |
|
Jun 2008 |
|
KR |
|
10-2010-0007484 |
|
Jan 2010 |
|
KR |
|
10-0991592 |
|
Nov 2010 |
|
KR |
|
10-1001045 |
|
Dec 2010 |
|
KR |
|
10-2011-0111374 |
|
Oct 2011 |
|
KR |
|
Primary Examiner: Le; Danh
Attorney, Agent or Firm: IP Legal Services, LLC
Parent Case Text
CROSS REFERENCE TO PRIOR APPLICATIONS
The present application is continuation application of U.S. patent
application Ser. No. 13/889,636 (filed on May 8, 2013), which
claims priority under 35 U.S.C. .sctn.119 to Korean Patent
Application No. 10-2012-0050853 (filed on May 14, 2012).
Claims
What is claimed is:
1. A method of adaptive call admission control in a femtocell base
station, the method comprising: receiving a call access request
from a user equipment; determining whether a call type is one of a
normal call and a preferred call based on the received call access
request corresponding to the call after an available call admission
capacity of the femtocell base station reaches a first limit; and
when the determined call type is the preferred call, performing
adaptive call admission control according to the determined call
type by accepting the received call access request for the
preferred call if the reserved call admission capacity has not
reached a second limit.
2. The method of claim 1, wherein the determining whether a call
type includes: determining the call type as the preferred call when
an associated call is assigned with a priority; otherwise,
otherwise, determining the call type as the normal call.
3. The method of claim 2, wherein for the determining the call type
as the preferred call, a preferred call includes at least one of a
voice over internet protocol (VoIP) call, a hand-in call from a
neighbor base station, and an emergency call.
4. The method of claim 1, the performing adaptive call admission
control includes: determining whether the available call admission
capacity of the femtocell base station reaches the second
limit.
5. The method of claim 4, wherein the accepting the received call
access request for the preferred call includes: declaring that the
reserved call admission capacity reaches the first limit when a
value of a parameter Reserve_User reaches a corresponding
threshold.
6. The method of claim 1, wherein when the call type is the normal
call, the performing adaptive call admission control includes:
accepting the received call access request for the normal call when
the available call admission capacity has not reached the first
limit.
7. The method of claim 6, wherein the accepting the received call
access request for the normal call includes: declaring that the
available call admission capacity reaches the first limit when the
value of the parameter Available_Active_User reaches a
predetermined threshold.
Description
BACKGROUND
The present disclosure relates to communication, more particularly,
to adaptive call admission control in a femtocell base station.
A femtocell may be a small and low-powered mobile communication
service area formed by a femtocell base station. The femtocell may
be also referred to as a small cell, a picocell, a microcell, and
an ubicell. The femtocell base station may be referred to as a
femtocell access point (AP). The femtocell base station may be also
referred to as a Home Node B (HNB) for a third generation
partnership project (3GPP) femtocell or a Home eNodeB (HeNB) for an
LTE femtocell. The femtocell may be typically designed for use in a
home or small business. The femtocell base station may be used to
improve a service quality or to guarantee a certain level of a
service quality at a certain area. In general, the femtocell base
station may be installed at a shadow area or an area having
deteriorated radio signals of macrocells. Furthermore, the
femtocell base station may be installed at a service area of a
macrocell for reducing a processing load of the macrocell.
Typically, a femtocell base station may form a comparatively small
service area and support the comparatively small number of users at
the same time. Accordingly, it may be required to efficiently
perform operations such as call admission control in the femtocell
base station due to the limited number of supporting users (i.e.,
user equipments) for providing a related service.
SUMMARY
This summary is provided to introduce a selection of concepts in a
simplified form that is further described below in the Detailed
Description. This summary is not intended to identify key features
or essential features of the claimed subject matter, nor is it
intended to be used to limit the scope of the claimed subject
matter.
Embodiments of the present invention overcome the above
disadvantages and other disadvantages not described above. Also,
the present invention is not required to overcome the disadvantages
described above, and an embodiment of the present invention may not
overcome any of the problems described above.
In accordance with an aspect of the present embodiments, a
femtocell base station may perform adaptive call admission control
according to a type of calls, such as a normal call and a preferred
call.
In accordance with another aspect of the present embodiments, a
femtocell base station may accept a call having a certain priority
although a call admission capacity of the femtocell base station
reaches a predetermined limit.
In accordance with still another aspect of the present embodiments,
an overall call admission capacity of a femtocell base station may
be divided into an available call admission capacity for accepting
any calls and a reserved call admission capacity for accepting a
call assigned with a priority and the femtocell base station may
adaptively perform call admission control based on the available
call admission capacity and the reserved call admission
capacity.
In accordance with an embodiment, a method may be provided for
adaptive call admission control in a base station. The method may
include receiving a call access request from a user equipment,
determining whether an available call admission capacity of the
base station reaches a first limit, determining whether the
received call access request is for a preferred call when the
available call admission capacity of the base station reaches the
first limit, determining whether a reserved call admission capacity
reaches a second limit when the received call access request is for
the preferred call, and allowing access of the user equipment
associated with the received call access request when the reserved
call admission capacity has not reached as second limit.
In accordance with another embodiment, an adaptive call admission
method in a femtocell base station may be provided. The method may
include receiving a call access request from a user equipment,
determining whether a call type is one of a normal call and a
preferred call based on the received call access request
corresponding to the call, and performing adaptive call admission
control according to the determined call type.
When the call type is the preferred call and when the reserved call
admission capacity has not reached the second limit, the received
call access request for the preferred call may be accepted. When
the call type is the normal call and when the available call
admission capacity has not reached the first limit, the received
call access request for the normal call may be accepted.
In accordance with still another embodiment, a base station may be
provided for adaptive call admission control. The base station may
include a receiver and a controller. The receiver may be configured
to receive a call access request from a user equipment. The
controller may be configured to determine whether an available call
admission capacity reaches a first limit, to determine whether a
reserved call admission capacity reaches a second limit, to
determine whether a type of a call is one of a normal call and a
preferred call based on the received call access request, and to
adaptively perform call admission control according to the
determined call type.
The controller may allow access of the user equipment associated
with the preferred call when the type of the call is the preferred
call and when the reserved call admission capacity has not reached
the second limit although the available call admission capacity
reaches the first limit. The controller may disallow access of the
user equipment associated with the normal call when the type of the
call is the normal call and when the available call admission
capacity reaches the first limit although the reserved call
admission capacity has not reached the second limit.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and/or other aspects of the present embodiments will
become apparent and more readily appreciated from the following
description of embodiments, taken in conjunction with the
accompanying drawings, of which:
FIG. 1 illustrates a femtocell included in a communication network
in accordance with at least one embodiment;
FIG. 2 shows a method for setting and updating call admission
control parameters in accordance with at least one embodiment;
FIG. 3 shows a method for adaptive call admission control in
accordance with at least one embodiment;
FIG. 4 shows a method for call admission control in accordance with
at least one embodiment; and
FIG. 5 shows a femtocell base station in accordance with at least
one embodiment.
DETAILED DESCRIPTION OF EMBODIMENTS
Reference will now be made in detail to exemplary embodiments of
the present invention, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals refer to
like elements throughout. The embodiments are described below, in
order to explain embodiments of the present invention by referring
to the figures.
In order to improve efficiency in operation of a femtocell base
station, a femtocell base station may perform call admission
control according to a type of user equipment such as a registered
user equipment and a non-registered user equipment. Particularly, a
femtocell base station may perform operations in three different
modes: a public mode, a private mode, and a flexible private mode.
In the public mode, a femtocell base station may allow any user
equipments to be accessed without discrimination of non-registered
user equipments and registered user equipments. In the private
mode, the femtocell base station may provide a relate service only
to registered user equipments. In the flexible private mode, the
femtocell base station may provide a related service not only to
registered user equipments but also to non-registered user
equipment. As described, the call admission control may be
performed differently according to the type of user equipments such
as the registered user equipments and the non-registered user
equipment.
As another example for improving the efficiency in a femtocell base
station, the femtocell base station may perform call admission
control according to a type of user equipment, non-CSG user
equipments and CSG user equipments. That is, the number of user
equipments that the femtocell base station will allow may be
restricted differently according to the type of user equipments.
The femtocell base station may perform call admission control in
three different access control modes: a closed access mode, a
hybrid access node, and an open access mode. The femtocell base
station may perform call admission control based on a call
admission capacity determined according to the access control
modes. In the closed access mode, femtocell base stations 130 and
150 only allow user equipments included in a closed subscriber
group (CSG) to access, which are referred to as CSG user
equipments. Accordingly, the call admission capacity may be the
number of CSG user equipments in the closed access mode. In the
hybrid access mode, femtocell base stations 130 and 150 allow not
only CSG user equipments but also user equipments in non-closed
subscriber group, which are referred to as non-CSG user equipments.
In the hybrid access mode, the call admission capacity may be
determined each for the number of CSG user equipments and the
number of non-CSG user equipments. In the open access mode,
femtocell base stations 130 and 150 allow any user equipments to be
accessed without discrimination of CSG user equipments and non-CSG
user equipments if a call admission capacity does not reach a
predetermined limit. Accordingly, the call admission capacity may
be determined as the total number of user equipments in service. As
described, the call admission control may be performed according to
the type of user equipments such as CSG user equipment and non-CSG
user equipment.
In accordance with at least one embodiment, a femtocell base
station may perform adaptive call admission control according to a
type of a call, such as a normal call and a preferred call. The
normal call may be a call without a priority assigned. The
preferred call may be a call assigned with a predetermined
priority, such as a voice over internet protocol (VoIP) call, a
hand-in call, and an emergency call. Call admission capacities may
be differently set according to the type of calls and the call
admission control may be performed based on the call admission
capacities. In order to perform adaptive call admission control, an
overall call admission capacity of a femtocell base station may be
divided into an available call admission capacity and a reserved
call admission capacity. Particularly, a femtocell base station may
admit a call access request of a preferred call when there is
remaining in the reserved call admission capacity although the
available call admission capacity already reaches a limit in
accordance with at least one embodiment. Hereinafter, a
communication network including a femtocell base station for
adaptive call admission control in accordance with at least one
embodiment will be described with reference to FIG. 1.
FIG. 1 illustrates a femtocell included in a communication network
in accordance with at least one embodiment.
Referring to FIG. 1, communication network 100 may include
heterogeneous cells such as macrocell 120 and a plurality of
femtocells 140 and 160. Communication network 100 may further
include core network 190 coupled to macrocell 120 and a plurality
of femtocells 140 and 160. Macrocell 120 may be formed and managed
by macrocell base station 110. First femtocell 140 may be formed
and managed by femtocell base station 130 and second femtocell 160
may be formed and managed by femtocell base station 150.
Typically, femtocell base stations 130 and 150 may be located
inside or outside macrocell 120, which is a service area of
macrocell base station 110. Accordingly, service areas of femtocell
base stations 130 and 150 may be included in that of macrocell base
station 110 or the service area of femtocell base stations 130 and
150 may be excluded from that of macrocell base station 110.
Furthermore, service areas of femtocell base stations 130 and 150
may overlap with that of macrocell base station 110. Femtocell base
stations 130 and 150 may be installed for improving a quality of
service (QoS) at a certain area or for maintaining a certain level
of a QoS at a certain area. For example, femtocell base stations
130 and 150 may be installed at indoor shadow areas or outdoor
shadow areas. Femtocell base stations 130 and 150 may be installed
at an area having excessive data traffic (i.e., congestion area)
and/or at a cell having excessive load.
As shown in FIG. 1, femtocell base stations 130 and 150 and
macrocell base station 110 are coupled to core network 190. Core
network 190 may be a central part of a telecommunication network
that provides various services including call routing to users who
are connected by an access network. Core network 190 may include a
plurality of nodes for aggregation, authentication, call
control/switching, charging, service invocation, and gateways.
In accordance with at least one embodiment, femtocell base stations
130 and 150 may perform adaptive call admission control according
to a type of a call, such as a normal call and a preferred call.
Particularly, femtocell base stations 130 and 150 may determine a
call admission capacity for normal calls and a reserved call
admission capacity only for the preferred calls and adaptively
control call admission based on the determined call admission
capacities. The call admission capacity for the normal call may be
referred to as an available call admission capacity and the call
admission capacity for the preferred call may be referred to as a
reserved call admission capacity. In case of the preferred call,
femtocell base stations 130 and 150 may allow user equipment 170 to
be accessed within a range of the reserved call admission capacity
although the available call admission capacity reaches a limit.
For example, femtocell base stations 130 and 150 may receive a call
access request from user equipment 170 and determine whether such
request is for a normal call or a preferred call. The normal call
may be a call without a priority assigned. The preferred call may
be a call assigned with a predetermined priority. For example, the
preferred call may be a call having a high Quality of Service (QoS)
priority, such as a voice over internet protocol (VoIP) call. The
preferred call may be a call handed off from neighbor cells.
Furthermore, the preferred call may be an emergency call, such as a
call to a specific place including a police station or a fire
department. The preferred call may include a VoIP call, a hand-in
call, and an emergency call, but the present invention is not
limited thereto. Accordingly the type of the requested call,
femtocell base stations 130 and 150 may perform adaptive call
admission control differently in accordance with at least one
embodiment.
When the call access request is for the normal call, femtocell base
stations 130 and 150 may allow requesting user equipment 170 to be
accessed until the available call admission capacity reaches a
predetermined normal call limit in accordance with at least one
embodiment. Such predetermined normal call limit may be set when
femtocell base stations 130 and 150 are initiated and updated
regularly during operation. Such setting and updating will be
described in detail with reference to FIG. 2. After the available
call admission capacity exceeds the predetermined limit, femtocell
base stations 130 and 150 may deny requesting user equipment 170 to
be accessed in accordance with at least one embodiment.
When the call access request is for the preferred call, femtocell
base stations 130 and 150 may allow requesting user equipment 170
to be accessed until the reserved call admission capacity reaches a
predetermined preferred call limit although the available call
admission capacity exceeds the predetermined normal call limit in
accordance with at least one embodiment. Such predetermined
preferred call limit may be set when femtocell base stations 130
and 150 are initiated and updated regularly during operation. Such
setting and updating will be described in detail with reference to
FIG. 2. After the reserved call admission capacity exceeds the
predetermined preferred call limit, femtocell base stations 130 and
150 may deny requesting user equipment 170 to be accessed in
accordance with at least one embodiment.
As described, femtocell base stations 130 and 150 may restrict the
number of user equipments (e.g., user equipment 170) to be accessed
according to the type of call in accordance with at least one
embodiment. The number of user equipments to be accessed for a
normal call may be determined as the available call admission
capacity. Furthermore, the number of user equipments 170 to be
accessed for a preferred call may be determined as the reserved
call admission capacity. That is, an overall call admission
capacity of femtocell base stations 130 and 150 may be divided into
an available call admission capacity and a reserved call admission
capacity. The overall call admission capacity may be the maximum
number of user equipments that femtocell base stations 130 and 150
can simultaneously manage or provide a related service to using
limited resources. The available call admission capacity may be the
number of users (i.e., user equipments) that femtocell base
stations 130 and 150 can allow access and simultaneously provide a
related service for normal calls. Such normal calls may include the
preferred calls. That is, a femtocell base station may allow access
of user equipments for any calls including a normal call and a
preferred call until the available call admission capacity reaches
the predetermined normal call admission limit. The reserved call
admission capacity may be the number of users (i.e., user
equipments) that femtocell base stations 130 and 150 can allow
access and simultaneously provide a related service for preferred
calls. The overall call admission capacity, the available call
admission capacity, and the reserved call admission capacity may be
defined using related parameters in accordance with at least one
embodiment.
For example, parameters related to adaptive call admission control
(i.e., call admission control parameters) may be defined in Table 1
below. Femtocell base stations 130 and 150 may set the call
admission control parameters when femtocell base stations 130 and
150 are initiated and update the call admission control parameters
during operation.
TABLE-US-00001 TABLE 1 Name Definition Max_Active_User The overall
call admission capacity: it might be the maximum number of users
(i.e., user equipments) that a femtocell base station can allow
access and provide a related service at the same time.
Available_Active_User The available call admission capacity: it
might be the number of users (i.e., user equipments) that a
femtocell base station can allow access and provide a related
service for normal calls (or any calls) at the same time.
Reserve_User The reserved call admission capacity: it might be the
number of users (i.e., user equipments) that a femtocell base
station can allow access and provide a related service only for the
preferred call at the same time. It might be the number of users
reserved for allowing a preferred call.
The parameter Max_Active_User may denote the overall call admission
capacity of respective femtocell base stations 130 and 150. That
is, the parameter Max_Active_User may be determined based on the
maximum number of users (i.e., user equipment) that respective
femtocell base stations 130 and 150 can allow access and provide a
service for calls, including a normal call and a preferred call, at
the same time. The parameter of Available_Active_User may denote
the available call admission capacity of respective femtocell base
stations 130 and 150. That is, the parameter Available_Active_User
may be determined based on the number of users (i.e., user
equipments) that respective femtocell base stations 130 and 150 can
allow access and provide a service for the normal call at the same
time. The parameter of Reserve_User may denote the reserved call
admission capacity of respective femtocell base stations 130 and
150. The parameter of Reserve_User may be determined based on the
number of reserved users (i.e., user equipments) that respective
femtocell base stations 130 and 150 can allow access and provide a
service for the preferred call at the same time. Accordingly, the
parameter of Max_Active_User may be equal to the sum of the
parameters of Available_Active_User and Reserve_User.
As described, the call admission control parameters may be set upon
the initiation of femtocell base stations 130 and 150. After the
initial setup of the call admission control parameters, femtocell
base stations 130 and 150 may regularly update call admission
control parameters in accordance with at least one embodiment. For
example, femtocell base stations 130 and 150 may update the
parameters of Reserve_User and Available_Active_User within a range
of the parameter of Max_Active_User. When updating the call
admission control parameters, femtocell base stations 130 and 150
may refer to statistical values calculated based on information
accumulated for a predetermined time period. Such information may
be obtained from call access requests or results of monitoring
status of a femtocell base station during a predetermined time
period. The information may include the number of user equipments
simultaneously in service at a femtocell base station in a certain
time period, the number of calls handed in from neighbor base
stations in a certain time period, the number of VoIP calls in a
certain time period, the number of calls invoked at each time
period, and the number of normal calls and the number of preferred
calls requested in a predetermined time period, and but the present
invention is not limited thereto.
For example, as accumulating information on call access requests
for a first time period and a second time period or as a result of
monitoring status of femtocell base stations 130 and 150 for a
first time period and a second time period, the average number of
hand-in calls in the first period is 3 and the average number of
hand-in calls in the second time period is 5 in femtocell base
stations 130 and 150. In this case, femtocell base stations 130 and
150 may set a value of the parameter Reserve_User in the first time
period as 3 and set a value of the parameter Reserve_User in the
second time period as 5. That is, femtocell base stations 130 and
150 may set the reserved call admission capacity for the first time
period as 3 and the reserved call admission capacity for the first
time period as 5.
For another example, as accumulating information on call access
requests for a first time period and a second time period or as a
result of monitoring status of femtocell base stations 130 and 150
for a first time period and a second time period, the average
number of hand-in calls and VoIP calls in a first time period may
be 4 and the average number of hand-in calls and VoIP calls in a
second time period may be 5 in femtocell base stations 130 and 150.
In this case, femtocell base stations 130 and 150 may set a value
of Reserve_User in the first time period as 4 and set a value of
Reserve_User in the second time period as 5. That is, femtocell
base stations 130 and 150 may set the reserved call admission
capacity for the first time period as 4 and the reserved call
admission capacity for the second time period as 5.
The values of all the call admission control parameters were
described as being set based on the accumulated information (i.e.,
information on call access requests or monitoring results), but the
present invention is not limited thereto. For example, femtocell
base stations 130 and 150 may determine one of the call admission
parameters Available_Active_User and Reserve_User based on the
accumulated information and calculate the other based on the
determined parameters. Particularly, femtocell base stations 130
and 150 may obtain a value of the parameter Available_Active_User,
which may be the number of normal calls to accept, by subtracting
the value of the parameter Reserve_User from a value of
Max_Active_User. Furthermore, femtocell base stations 130 and 150
may obtain a value of the parameter Reserve_User, which is the
number of preferred calls to accept, by subtracting the value of
the parameter Available_Active_User from a value of
Max_Active_User. Accordingly, femtocell base stations 130 and 150
may calculate one of the statistic values of the parameters
Available_Active_User and Reserve_User based on the accumulated
information and updates the call admission control parameters based
on the calculated statistic value.
As described above, an overall call admission capacity may be
divided into the available call admission capacity and the reserved
call admission capacity, and the available call admission capacity
and the reserved call admission capacity may be set and updated
based on a result of monitoring status of a respective femtocell
base station for a certain time period in accordance with at least
one embodiment. Based on such available call admission capacity and
reserved call admission capacity, femtocell base stations 130 and
150 may perform adaptive call admission control in accordance with
at least one embodiment of the present disclosure. For example,
femtocell base stations 130 and 150 may allow access of user
equipments requesting for both of normal calls and preferred calls
until the number of user equipments requesting for normal calls and
preferred calls reaches to the value of the parameter
Available_Active_User. After the number of user equipments
requesting for normal calls equals to the value of the parameter
Available_Active_User, femtocell base stations 130 and 150 may
allow access of user equipments requesting for the preferred calls
until the number of user equipments requesting for the preferred
calls reaches the value of the parameter Reserve_User.
For another example, femtocell base stations 130 and 150 may allow
access of user equipments requesting normal calls within a range of
the parameter Available_Active_User. Furthermore, femtocell base
stations 130 and 150 may allow access of user equipments requesting
preferred calls within a range of the parameter Reserve_User. When
the number of user equipments simultaneously served by a
corresponding femtocell base station for normal calls reaches the
value of the parameter Available_Active_User, femtocell base
stations 130 and 150 deny requests by new user equipment for the
normal call. When the number of user equipments simultaneously
served by a corresponding femtocell base station for preferred
calls reaches the value of the parameter Reserve_User, femtocell
base stations 130 and 150 deny requests by new user equipment for
the preferred call. That is, femtocell base stations 130 and 150
deny access of new user equipment requesting for the preferred
call.
In some embodiments, femtocell base stations 130 and 150 may
additionally allow access of user equipments for a preferred call
if the number of user equipments in service for the normal calls
does not reach a value of the parameter Available_Active_User
although the number of user equipments for the preferred call
already reaches the value of the parameter Reserve_User. Such
adaptive call admission control will be described in more detail
with reference to FIG. 3 and FIG. 4.
As described, femtocell base stations 130 and 150 may adaptively
control access of user equipments based on the call admission
control parameters in accordance with at least one embodiment. Such
call admission control parameters may be set upon the initiation of
a femtocell base station and updated during operation. Such setup
and update operation will be described with reference to FIG. 2,
hereinafter. The setup and update operation will be described based
on femtocell base station 130, but the present invention is not
limited thereto. The same operation will be applied to any
femtocell base stations including femtocell base station 150.
FIG. 2 shows a method for setting and updating call admission
control parameters in accordance with at least one embodiment.
Referring to FIG. 2, femtocell base station 130 may be initiated
when power is on at step S2010. For example, femtocell base station
130 may be installed a predetermined location such as an indoor
shadow area or an outdoor shadow area. After the installation,
femtocell base station 130 is powered on and initiated for
providing a related service.
At step S2020, femtocell base station 130 may initially set call
admission control parameters upon the initiation of femtocell base
station 130. For example, femtocell base station 130 may set values
of the call admission control parameters such as Max_Active_User,
Reserve_User, and Available_Active_User. As described, call
admission control parameters Max_Active_User, Reserve_User, and
Available_Active_User may respectively denote an overall call
admission capacity, an available call admission capacity and a
reserved call admission capacity.
In order to set the call admission control parameters, femtocell
base station 130 may receive information entered from a user
through a predetermined input device provided with femtocell base
station 130 or receive information transmitted from management
servers (not shown) of core network 190. Particularly, femtocell
base station 130 may receive values for all of the call admission
control parameters Max_Active_User, Reserve_User, and
Available_Active_User from a user or management servers in core
network 190. Femtocell base station 130 may set all of the call
admission control parameters based on the received values.
Furthermore, femtocell base station 130 may receive values for at
least one of the call admission control parameters Max_Active_User,
Reserve_User, and Available_Active_User and calculate values of the
others based on the received value. For example, femtocell base
station 130 may receive values for the call admission control
parameters Max_Active_User and Reserve_User and calculate a value
for the call admission control parameter Available_Active_User
based on the received values. In addition, femtocell base station
130 may receive values for the call admission control parameters
Max_Active_User and Available_Active_User and calculate a value for
the call admission control parameter Reserve_User based on the
received values. That is, the overall admission capacity, the
available call admission capacity, and the reserved call admission
capacity may be set based on the information received from a user
or from a management server in core network 190.
At step S2030, femtocell base station 130 may perform adaptive call
admission control based on the initial setup of the call admission
control parameters Max_Active_User, Reserve_User, and
Available_Active_User and provide communication services to
accessed user equipments. For example, femtocell base station 130
allows access of user equipment requesting a normal call and a
preferred call until the number of user equipments in service for
the normal call and the preferred call reaches a value of the
parameter of Available_Active_User and denies access of user
equipment requesting a normal call after the number of user
equipments in service for the normal call and the preferred call
reaches a value of the parameter of Available_Active_User.
Furthermore, femtocell base station 130 still allows access of user
equipment requesting a preferred call if the reserved call
admission capacity does not reach the predetermined limit. Such
adaptive call admission control will be described in detail with
reference to FIG. 3.
While performing the adaptive call admission control, femtocell
base station 130 may temporally store and accumulate information on
call access requests whenever the call access requests are received
at step S2040. Alternatively, while performing the adaptive call
admission control, femtocell base station 130 may monitor status
thereof and stores and accumulate information on the monitoring
results for a certain time period in order to update the call
admission control parameters at step S2040. For example, femtocell
base station 130 monitors status thereof and store and accumulate
information related to the parameters of Reserve_User and
Available_Active_User. When updating the call admission control
parameters, femtocell base stations 130 and 150 may refer to
statistical values calculated based on information accumulated for
a predetermined time period. Such information may be accumulated
information on call access requests or results of monitoring status
of a femtocell base station during a predetermined time period. For
example, femtocell base station 130 may collect the information on
the number of user equipments in service at a certain time period,
the number of calls handed off from neighbor base stations in a
certain time period, the number of VoIP calls in a certain time
period, the number of calls invoked at each time period, and the
number of normal calls and the number of preferred calls requested
in a predetermined time period, and but the present invention is
not limited thereto. Femtocell base station 130 may accumulate the
collected information in a memory (e.g., memory 590 of FIG. 5).
At step S2050, femtocell base station 130 may determine whether a
predetermined time period T is passed. For example, femtocell base
station 130 regularly updates the call admission parameters at the
predetermined time period T.
When the predetermined time period T does not pass (No--S2050),
femtocell base statin 130 may continuously perform the adaptive
call admission control at step S2030.
When the predetermined time period T passes (Yes--S2050), femtocell
base station 130 may calculate statistical values related to the
call admission control parameters based on the stored and
accumulated information at step S2060. For example, femtocell base
station 130 may obtain or calculate the average number of normal
calls and the average number of preferred calls in the time period
T based on the accumulated information stored in memory 590.
At step S2070, femtocell base station 130 may update the call
admission control parameters based on the calculated statistical
values. For example, femtocell base station 130 obtains 3 as the
average number of hand-in calls in the first time period T1 and 5
as the average number of hand-in calls in the second time period
T2. In this case, femtocell base station 130 sets the call
admission control parameter of Reserve_User as 3 for the first time
period T1. Furthermore, femtocell base station 130 sets the call
admission control parameter of Reserve_User as 5 for the second
time period T2. For example, femtocell base station 130 obtains 4
as the average number of hand-in calls and VoIP calls in the first
time period T1 and 5 as the average number of hand-in calls and
VoIP calls in the second time period T2. In this case, femtocell
base station 130 sets the call admission control parameter of
Reserve_User as 4 for the first time period T1 and as 5 for the
second time period T2. In addition, femtocell base station 130 may
set the call admission control parameter of Available_Active_User
by subtracting the value of Reserve_User from the value of
Max_Active_User.
After updating, femtocell base station 130 may continuously provide
a communication service by performing adaptive call access control
based on the updated parameters at step S2030. After a
predetermined time passes (Yes--S2040), the value of the parameter
Reserve_User users may be updated repeatedly based on the
accumulated information.
As described, the call admission control parameters may be
initially set upon the initiation of a femtocell base station and
updated at a regular interval based on the accumulated information
during operation in accordance with at least one embodiment.
Femtocell base stations 130 and 150 may perform the adaptive call
admission control based on the call admission control parameters
(i.e., the available call admission capacity and the reserved call
admission capacity) in accordance with at least one embodiment.
Such operation will be described in more detail with reference to
FIG. 3.
FIG. 3 shows a method for adaptive call admission control in
accordance with at least one embodiment.
Referring to FIG. 3, a call access request may be received at step
S3010. For example, femtocell base station 130 may receive a call
access request from user equipment 170. Such a call access request
may be for a normal call or a preferred call. As described, the
preferred call may be a call assigned with a predetermined
priority. The normal call may be any call without a predetermined
priority assigned. Such a preferred call may be a hand-in call,
which is handed in from neighbor base stations, a VoIP call, and an
emergency call, but the present invention is not limited thereto.
As described, femtocell base station 130 may adaptively perform
call admission control according to a type of a call in accordance
with at least one embodiment.
At step S3020, determination may be made as to whether a call
admission control parameter Available_Active_User is equal to 0.
For example, femtocell base station 130 may determine whether an
available call admission capacity reaches a predetermined limit
based on the call admission control parameter of
Available_Active_User. That is, femtocell base station 130 may
determine whether there are remaining resources to accept calls
from user equipments based on the call admission control parameter
of Available_Active_User. In order to determine, femtocell base
station 130 may compare a value of Available_Active_User with `0`.
When the value of Available_Active_User is equal to `0`, femtocell
base station 130 determines that the available call admission
capacity reaches the limit or that there is no available resource
to accept calls. Otherwise, femtocell base station 130 determines
that the available call admission capacity dose not reaches the
limit or that there are some available resources to accept calls
(i.e., to allow access of femtocell base statin 130 requesting the
call).
When the parameter Available_Active_User is not equal to 0
(No--S3020), user equipment requesting the call may be allowed
access at step S3030. For example, femtocell base station 130 may
allow access to user equipment 170 requesting the call when the
available call admission capacity does not reach the predetermined
limit.
After allowing, a value of the parameter Available_Active_User may
decrease by a predetermined value at step S3040. For example,
femtocell base station 130 decreases the value of the parameter
Available_Active_User by one.
When the value of the parameter Available_Active_User is equal to 0
(Yes--S3020), determination may be made as to whether the call
access request is for a preferred call at step S3050. For example,
when the available call admission capacity reaches the
predetermined limit, femtocell base station 130 determines whether
the call access request is for a preferred call.
When the call access request is not for the preferred call
(No--S3050), the call access request may be denied at step S3090.
For example, femtocell base station 130 denies the call access
request from user equipment 170 because the available call
admission capacity reaches the predetermined limit and the call
access request is not for the preferred call. Such operation may
include controlling user equipment 170 to access the other cells
(i.e., neighbor base stations) or releasing a connection to user
equipment 170.
When the call access request is for the preferred call
(Yes--S3050), determination may be made as to whether the call
admission control parameter Reserve_User is equal to 0 at step
S3060. For example, femtocell base station 130 may determine
whether the reserved call admission capacity reaches a
predetermined limit. When the value of the parameter Reserve_User
is not equal to 0, femtocell base station 130 may determine there
are remaining resources for allowing access of user equipment for
the preferred call. When the value of the parameter Reserve_User is
equal to 0, femtocell base station 130 may determine there are no
reserved resources left for allowing access of user equipment for
the preferred call.
When the parameter Reserve_User is not equal to 0 (No--S3060), the
call access request may be accepted at step S3070. For example,
when the reserved call admission capacity does not reach the
predetermined limit, femtocell base station 130 allows user
equipment 170 requesting the preferred call to be accessed for the
preferred call.
After allowing, the value of the parameter Reserve_User may
decrease by a predetermined number at step S3080. For example,
femtocell base station decreases the value of Reserve_User
decreases by 1.
When the parameter Reserve_User is equal to 0 (Yes--S3060), the
call access request may be denied at step S3090. For example, when
the reserved call admission capacity reaches the predetermined
limit, femtocell base station 130 does not allow access of user
equipment 170 requesting the preferred call.
As described, femtocell base station 130 may allow access of user
equipments 170 if user equipment 170 requests the preferred call
although the available call admission capacity reaches the
predetermined limit. That is, some resources may be reserved for
the preferred calls in order to allow access of user equipment
requesting the preferred calls although the call admission capacity
reaches a certain limit. In this way, predetermined types of calls
may have a privilege to be processed in accordance with at least
one embodiment of the present disclosure. Accordingly, the overall
QoS may be maximized using limited resources in accordance with at
least one embodiment.
FIG. 4 shows a method for call admission control in accordance with
at least one embodiment.
Referring to FIG. 4, a call access request may be received at step
S4010. For example, femtocell base station 130 may receive a call
access request from user equipment 170. Such a call access request
may be for a normal call or a preferred call. The preferred call
may be a call assigned with a predetermined priority. Such
preferred call may be a hand-in call, which is handed in from
neighbor base stations, a VoIP call, and an emergency call, but the
present invention is not limited thereto.
At step S4020, determination may be made as to whether the call
access request is for a preferred call or not at step S4020. For
example, femtocell base station 130 determines whether the call
access request is for a call assigned with a predetermined
priority, such as a VoIP call, a hand-in call, and an emergency
call. Femtocell base station 130 determines that the call access
request is for the preferred call when the call access request is
for the call assigned with the predetermined priority. Otherwise,
femtocell base station 130 determines that the call access request
is not for the preferred call.
When the call access request is the preferred call (Yes--S4030),
determination may be made as to whether the call admission control
parameter Reserve_User is equal to 0 at step S4030. For example,
femtocell base station 130 determines whether the reserved call
admission capacity reaches a predetermined limit. When the value of
the parameter Reserve_User is not equal to 0, femtocell base
station 130 may determine there are remaining resources for
allowing access of user equipment for the preferred call. When the
value of the parameter Reserve_User is equal to 0, femtocell base
station 130 may determine there are no reserved resources left for
allowing access of user equipment for the preferred call.
When the parameter Reserve_User is not equal to 0 (No--S4030), the
call access request may be accepted at step S4040. For example,
when the reserved call admission capacity does not reach the
predetermined limit, femtocell base station 130 allows user
equipment 170 requesting the preferred call to be accessed.
After allowing, the value of the parameter Reserve_User may
decrease by a predetermined number at step S4050. For example,
femtocell base station decreases the value of Reserve_User
decreases by 1.
When the parameter Reserve_User is equal to 0 (Yes--S4030), the
call access request may be denied at step S4070. For example, when
the reserved call admission capacity reaches the predetermined
limit, femtocell base station 130 does not allow access of user
equipment 170 requesting the preferred call.
When the call access request is not the preferred call (No--S4020),
determination may be made as to whether a call admission control
parameter Available_Active_User is equal to 0 at step S4060. For
example, femtocell base station 130 may determine whether an
available call admission capacity reaches a predetermined limit
based on the call admission control parameter of
Available_Active_User when the call access request is not for the
preferred call.
When the parameter Available_Active_User is not equal to 0
(No--S4060), user equipment requesting the call may be allowed to
be accessed at step S4080. For example, femtocell base station 130
allows access of user equipment 170 to be accessed when the
available call admission capacity does not reach the predetermined
limit.
After allowing, a value of the parameter Available_Active_User may
decrease by a predetermined value at step S4090. For example,
femtocell base station 130 decreases the value of the parameter
Available_Active_User by one.
When the parameter Available_Active_User is equal to 0
(Yes--S4060), the call access request may be denied at step S4070.
For example, when the available call admission capacity reaches the
predetermined limit, femtocell base station 130 does not allow
access of user equipment 170.
As described, femtocell base stations 130 and 150 may accept a call
request if the requested call has a certain priority assigned
although call admission capacity thereof reaches or exceeds a
certain limit in accordance with at least one embodiment.
Hereinafter, a femtocell base station for adaptive call admission
control will be described with reference to FIG. 5. Femtocell base
station 130 will be described representatively, but the present
invention is not limited thereto. Although femtocell base station
150 is not described, femtocell base station 150 may have a similar
or the same configuration to that of femtocell base station
130.
FIG. 5 shows a femtocell base station in accordance with at least
one embodiment.
Referring to FIG. 5, femtocell base station 130 may include
parameter setup unit 510, receiver 530, admission controller 550,
processor 570, and memory 590.
Parameter setup unit 510 may set parameters related to adaptive
call admission control, which may be referred to as call admission
control parameters. For example, call admission control parameters
may include Max_Active_User, Reserve_User, and
Available_Active_User. As described, the parameter Max_Active_User
may denote an overall call admission capacity, the parameter
Reserve_User may denote a reserved call admission capacity for a
preferred call, and the parameter Available_Active_User may denote
an available call admission capacity. The available call admission
capacity may be equal to subtraction of the reserved call admission
capacity from the overall call admission capacity.
Parameter setup unit 510 may set the call admission parameters when
femtocell base station 130 is initiated, for example, when
femtocell base station 130 is turned on. The present invention,
however, is not limited thereto. For example, parameter setup unit
510 may regularly set the call admission parameters at a certain
interval. Furthermore, parameter setup unit 510 may refer inputs
from users for setting up the call admission parameters or respond
to the control of a management server for setting up the call
admission parameters.
Such initial setup call admission parameters may be updated at a
certain interval. For example, parameter setup unit 510 may update
the initial setup call admission parameters including Reserve_User
and Available_Active_User. Particularly, parameter setup unit 510
may update Reserve_User and Available_Active_User based on
statistical values calculated based on results of monitoring status
of a respective femtocell base station. Such calculation may be
performed by processor 570.
For example, processor 570 calculates that the average number of
hand-in calls in a first time period is three and the average
number of hand-in calls in a second time period is five. In this
case, parameter setup unit 510 may set up the parameter
Reserve_User in the first time period as three and the parameter
Reserve_User in the second time period as five. Furthermore,
parameter setup unit 510 may set up the parameter
Available_Active_User in the first time period as seven and the
Available_Active_User in the second time period as five.
Receiver 530 may receive a call access request from user equipment
170. In response to the control of controller 550, such a call
access request may be accepted or denied. In addition, receiver 530
may deliver information on the call access request to processor 570
whenever receiver 530 receives the call access request.
Processor 570 may receive information on the call access request
from receiver 530 and temporally store and accumulate the received
information in memory 590. Alternatively, processor 570 may be
provided with results of monitoring statuses thereof and temporally
store and accumulate the monitoring results in memory 590.
Processor 570 may calculate the average number of normal calls
(i.e., calls not assigned with a predetermined priority) and the
average number of preferred calls (i.e., calls assigned with a
predetermined priority) in each time period based on the
accumulated information. After calculation, processor 570 may
deliver the calculated statistical values to parameter setup unit
510.
Controller 550 may perform adaptive call access control on the
received call request based on the call admission control
parameters from parameter setup unit 510.
In accordance with at least one embodiment, controller 550 may
accept calls within a range of the available call admission
capacity (i.e., the parameter Available_Active_User) at first. When
the available call admission capacity (i.e., the parameter
Available_Active_User) reaches a certain number, controller 550 may
additionally accept only the preferred calls within a range of the
reserved call admission capacity (i.e., the parameter
Reserve_User).
In some embodiments, controller 550 may accept normal calls (i.e.,
calls not assigned with a predetermined priority) within a range of
the available call admission capacity (i.e., Available_Active_User)
and accepts preferred calls within a range of the reserved call
admission capacity (i.e., Reserve_User). Accordingly, when the
number of user equipments in service for normal calls is equal to a
value of the parameter Available_Active_User, controller 550 may
not accept new calls. When the number of user equipments in service
for preferred calls is equal to a value of the parameter
Reserve_User, controller 550 may not accept new preferred
calls.
When the number of user equipments in service for the preferred
calls is equal to the value of the parameter Reserve_User and when
the number of user equipments in service for the normal calls is
smaller than the value of the parameter Available_Active_User,
controller 550 may additionally accept preferred calls the value of
the parameter Available_Active_User becomes 0.
Reference herein to "one embodiment" or "an embodiment" means that
a particular feature, structure, or characteristic described in
connection with the embodiment can be included in at least one
embodiment of the invention. The appearances of the phrase "in one
embodiment" in various places in the specification are not
necessarily all referring to the same embodiment, nor are separate
or alternative embodiments necessarily mutually exclusive of other
embodiments. The same applies to the term "implementation."
As used in this application, the word "exemplary" is used herein to
mean serving as an example, instance, or illustration. Any aspect
or design described herein as "exemplary" is not necessarily to be
construed as preferred or advantageous over other aspects or
designs. Rather, use of the word exemplary is intended to present
concepts in a concrete fashion.
Additionally, the term "or" is intended to mean an inclusive "or"
rather than an exclusive "or". That is, unless specified otherwise,
or clear from context, "X employs A or B" is intended to mean any
of the natural inclusive permutations. That is, if X employs A; X
employs B; or X employs both A and B, then "X employs A or B" is
satisfied under any of the foregoing instances. In addition, the
articles "a" and "an" as used in this application and the appended
claims should generally be construed to mean "one or more" unless
specified otherwise or clear from context to be directed to a
singular form.
Moreover, the terms "system," "component," "module," "interface,",
"model" or the like are generally intended to refer to a
computer-related entity, either hardware, a combination of hardware
and software, software, or software in execution. For example, a
component may be, but is not limited to being, a process running on
a processor, a processor, an object, an executable, a thread of
execution, a program, and/or a computer. By way of illustration,
both an application running on a controller and the controller can
be a component. One or more components may reside within a process
and/or thread of execution and a component may be localized on one
computer and/or distributed between two or more computers.
The present invention can be embodied in the form of methods and
apparatuses for practicing those methods. The present invention can
also be embodied in the form of program code embodied in tangible
media, non-transitory media, such as magnetic recording media,
optical recording media, solid state memory, floppy diskettes,
CD-ROMs, hard drives, or any other machine-readable storage medium,
wherein, when the program code is loaded into and executed by a
machine, such as a computer, the machine becomes an apparatus for
practicing the invention. The present invention can also be
embodied in the form of program code, for example, whether stored
in a storage medium, loaded into and/or executed by a machine, or
transmitted over some transmission medium or carrier, such as over
electrical wiring or cabling, through fiber optics, or via
electromagnetic radiation, wherein, when the program code is loaded
into and executed by a machine, such as a computer, the machine
becomes an apparatus for practicing the invention. When implemented
on a general-purpose processor, the program code segments combine
with the processor to provide a unique device that operates
analogously to specific logic circuits. The present invention can
also be embodied in the form of a bitstream or other sequence of
signal values electrically or optically transmitted through a
medium, stored magnetic-field variations in a magnetic recording
medium, etc., generated using a method and/or an apparatus of the
present invention.
It should be understood that the steps of the exemplary methods set
forth herein are not necessarily required to be performed in the
order described, and the order of the steps of such methods should
be understood to be merely exemplary. Likewise, additional steps
may be included in such methods, and certain steps may be omitted
or combined, in methods consistent with various embodiments of the
present invention.
As used herein in reference to an element and a standard, the term
"compatible" means that the element communicates with other
elements in a manner wholly or partially specified by the standard,
and would be recognized by other elements as sufficiently capable
of communicating with the other elements in the manner specified by
the standard. The compatible element does not need to operate
internally in a manner specified by the standard.
No claim element herein is to be construed under the provisions of
35 U.S.C. .sctn.112, sixth paragraph, unless the element is
expressly recited using the phrase "means for" or "step for."
Although embodiments of the present invention have been described
herein, it should be understood that the foregoing embodiments and
advantages are merely examples and are not to be construed as
limiting the present invention or the scope of the claims. Numerous
other modifications and embodiments can be devised by those skilled
in the art that will fall within the spirit and scope of the
principles of this disclosure, and the present teaching can also be
readily applied to other types of apparatuses. More particularly,
various variations and modifications are possible in the component
parts and/or arrangements of the subject combination arrangement
within the scope of the disclosure, the drawings and the appended
claims. In addition to variations and modifications in the
component parts and/or arrangements, alternative uses will also be
apparent to those skilled in the art.
* * * * *